PROJECTSUMMARY PainmanagementisamajorpublichealthproblemintheUnitedStates.Opioidslikemorphinearewidelyused totreatseverepain,buttheypossesslimitationssuchasabuseliabilityandpotentiallylethalrespiratory depressionthathavefedintothecurrentopioidpublichealthcrisis.Theendocannabinoidsystem,which includescannabinoidreceptors(CBRs),endogenouscannabinoid(eCB)lipidneurotransmitters,andenzymes responsibleforthesynthesisanddegradationofeCBs,hasemergedasapromisingsourceoftargetsfor developmentofcandidatenon-opioidanalgesics.Inparticular,theenzymemonoacylglycerollipase(MAGL) breaksdowntheeCBagonist2-arachidonoylglycerol(2-AG),andMAGLinhibitioncanincrease2-AGlevels, increaseCBRactivation,andpotentiallyinhibitpain-relatedactivityinneuralpathwaysthatmediatedifferent painbehaviors.ThisF31applicationproposesresearchthatwillevaluatetheeffectivenessoftheMAGL inhibitorMJN110toalleviateabatteryofpain-relatedbehavioralandneurochemicalendpointsinadultmale andfemalemicefollowingintraperitonealadministrationofdilutelacticacid(IPacid)asanacute,visceral,and physiologicallyrelevantnoxiousstimulus.Aim1willdetermineMJN110effectivenesstoalleviateIPacid- inducedsensoryandaffectivepain-relatedbehaviorsmediatedbyspinalandcentralpain-processing pathways.TheeffectsofMJN110willbecomparedtoclinicallyeffectivepositive-controlanalgesics(themu opioidreceptoragonistoxycodoneandthecyclooxygenaseinhibitorketoprofen),non-analgesicnegative controlsthatnonspecificallydepressorstimulategeneralbehavior(theGABA-Areceptorpositiveallosteric modulatordiazepamanddopamine/norepinephrinetransporterinhibitoramphetamine),andthedirectCBR agonist?9-tetrahydrocannabinol(THC).Aim2willdetermineMJN110effectivenesstoinhibitIPacid-induced activationofsensoryandaffectivepainpathways.Neuronalactivationwillbeassessedwith immunohistochemicalandfluorescentinsituhybridizationoftheproto-oncogenecFos,andthechemical phenotypeofcFos-positiveneuronswillbedeterminedusingdouble-labelingwithantibodiesselectivefor markersinglutamaterigicvs.GABAergicneurons.Aim3willusehigh-performanceliquidchromatography- massspectrometrytodetermineMJN110effectivenesstomodulatepain-relatedchangeslipidomicprofilesof fattyacids,oxilipins,andN-acylethanoliminesinsensoryandaffectivepainpathways.Overall,theproposed researchwillprovideadetailedevaluationoftheantinocicpetiveeffectivenessofMJN110foracutenoxious stimuli,aswellasimproveourunderstandingoftheeCBsystem?sroleinacuteinflammatorypainsignaling andantinociceptionthroughcomparativeanalysesofclinically-relevantpain-relatedbehaviorsand neurochemicalandlipidomiccorrelates.